         (s/map (fn [record-or-key-value]
                  (select-one session entity key record-or-key-value opts)))
         (s/realize-each)
+        (s/filter some?)
         return)))
 
 (defn select-many

          (s/map (fn [record-or-key-value]
                   (select-one-instance session entity key record-or-key-value opts)))
          (s/realize-each)
          return))))

(defn select-many-instances

                   (select-buffered session entity key record-or-key-value opts)))
          (s/realize-each)
          (s/concat)
          (s/filter some?)
          return))))

(defn select-many-cat
